%I #6 Nov 07 2021 18:54:08
%S 0,6,24,60,120,210,336,504,72,180,33,96,195,336,525,768,1071,1440,342,
%T 600,168,330,552,840,1200,1638,2160,2772,870,1320,465,768,1155,1632,
%U 2205,2880,3663,4560,1716,2400,984,1470,2064,2772,3600,4554,5640,6864
%N a(n)= n * digital sum(n-1) * digital sum(n+1)
%F a(n)=n*A007953(n-1)*A007953(n+1).
%e a(8)=8*ds(7)*ds(9)=8*7*9=504.
%e a(15)=15*ds(14)*ds(16)=15*5*7=525.
%e a(26)=26*ds(25)*ds(27)=26*7*9.
%t Table[n Total[IntegerDigits[n-1]]Total[IntegerDigits[n+1]],{n,50}] (* _Harvey P. Dale_, Nov 07 2021 *)
%K nonn,base,easy
%O 1,2
%A _Claudio Meller_, May 30 2009
|